The Mn, Cu, Zn, Ni and Cd contents of the soil were evaluated by means of DTPA extraction according to the Lindsay and Norvell (1969) method. The soil samples analysed came from agricultural fields from all over Catalonia, stored in the Soil Samples Bank of the Catalonia Soil Map (DARP). The results where grouped by agricultural systems in function of the origin of the samples as a significant reduction in the variation of the different factors for each agricultural system may
be expected. A statistical analysis of the
median values from the different agricultural systems was carried out, together with the median values for the two
soil depths studied and an agronomic
interpretation.
The results show that the soils from
the highly intensive horticultural system
in the Maresme have the highest contents of the metals studied. On the
other hand, it is clear that the soil values encountered are conditioned by
the parent soil material as well as by
anthropogenic activity. The Cu and Zn
contents in the samples from the Maresme are well above the minimum contents considered satisfactory agronomically.